This is quite a difficult problem and none of us could ____ a solution to it. [ ]

单项填空Only in this way______ get ready for the coming mid-term examinations.

When I wanted to express my thanks to him，words ___ me. I just held his hands firmly and choked.

Someone is knocking at the door, who _____ it be?It _____ be Danny. He’s in hospital for some time. [ ]

nspot came into its active stage,__________ that happens once every eleven years